03468nas a2200265   4500008004100000022001400041245013200055210006900187260000800256300001400264490000800278520267200286100001902958700001702977700001902994700001503013700001803028700001903046700001703065700002003082700001903102700001403121700001903135856004803154       2016                        eng d  a1095-957200aAlpha power indexes task-related networks on large and small scales: A multimodal ECoG study in humans and a non-human primate.0 aAlpha power indexes taskrelated networks on large and small scal  cJul  a122–1310 v1343 aPerforming different tasks, such as generating motor movements or processing sensory input, requires the recruitment of specific networks of neuronal populations. Previous studies suggested that power variations in the alpha band (8-12Hz) may implement such recruitment of task-specific populations by increasing cortical excitability in task-related areas while inhibiting population-level cortical activity in task-unrelated areas (Klimesch et al., 2007; Jensen and Mazaheri, 2010). However, the precise temporal and spatial relationships between the modulatory function implemented by alpha oscillations and population-level cortical activity remained undefined. Furthermore, while several studies suggested that alpha power indexes task-related populations across large and spatially separated cortical areas, it was largely unclear whether alpha power also differentially indexes smaller networks of task-related neuronal populations. Here we addressed these questions by investigating the temporal and spatial relationships of electrocorticographic (ECoG) power modulations in the alpha band and in the broadband gamma range (70-170Hz, indexing population-level activity) during auditory and motor tasks in five human subjects and one macaque monkey. In line with previous research, our results confirm that broadband gamma power accurately tracks task-related behavior and that alpha power decreases in task-related areas. More importantly, they demonstrate that alpha power suppression lags population-level activity in auditory areas during the auditory task, but precedes it in motor areas during the motor task. This suppression of alpha power in task-related areas was accompanied by an increase in areas not related to the task. In addition, we show for the first time that these differential modulations of alpha power could be observed not only across widely distributed systems (e.g., motor vs. auditory system), but also within the auditory system. Specifically, alpha power was suppressed in the locations within the auditory system that most robustly responded to particular sound stimuli. Altogether, our results provide experimental evidence for a mechanism that preferentially recruits task-related neuronal populations by increasing cortical excitability in task-related cortical areas and decreasing cortical excitability in task-unrelated areas. This mechanism is implemented by variations in alpha power and is common to humans and the non-human primate under study. These results contribute to an increasingly refined understanding of the mechanisms underlying the selection of the specific neuronal populations required for task execution.1 ade Pesters, A.1 aCoon, W., G.1 aBrunner, Peter1 aGunduz, A.1 aRitaccio, A L1 aBrunet, N., M.1 ade Weerd, P.1 aRoberts, M., J.1 aOostenveld, R.1 aFries, P.1 aSchalk, Gerwin  uhttp://www.ncbi.nlm.nih.gov/pubmed/2705796001043nas a2200157   4500008004100000022001400041245014200055210006900197260000800266300001200274490000800286520050700294100001700801700001900818856004800837       2016                        eng d  a1872-678X00aA method to establish the spatiotemporal evolution of task-related cortical activity from electrocorticographic signals in single trials.0 amethod to establish the spatiotemporal evolution of taskrelated   cSep  a76–850 v2713 aProgress in neuroscience depends substantially on the ability to establish the detailed spatial and temporal sequence of neuronal population-level activity across large areas of the brain. Because there is substantial inter-trial variability in neuronal activity, traditional techniques that rely on signal averaging obscure where and when neuronal activity occurs. Thus, up to the present, it has been difficult to examine the detailed progression of neuronal activity across large areas of the brain.1 aCoon, W., G.1 aSchalk, Gerwin  uhttp://www.ncbi.nlm.nih.gov/pubmed/2742730102115nas a2200205   4500008004100000022001400041245009100055210006900146260000800215300001400223490000800237520151200245100001701757700001501774700001901789700001801808700001601826700001901842856004801861       2016                        eng d  a1095-957200aOscillatory phase modulates the timing of neuronal activations and resulting behavior.0 aOscillatory phase modulates the timing of neuronal activations a  cJun  a294–3010 v1333 aHuman behavioral response timing is highly variable from trial to trial. While it is generally understood that behavioral variability must be due to trial-by-trial variations in brain function, it is still largely unknown which physiological mechanisms govern the timing of neural activity as it travels through networks of neuronal populations, and how variations in the timing of neural activity relate to variations in the timing of behavior. In our study, we submitted recordings from the cortical surface to novel analytic techniques to chart the trajectory of neuronal population activity across the human cortex in single trials, and found joint modulation of the timing of this activity and of consequent behavior by neuronal oscillations in the alpha band (8-12Hz). Specifically, we established that the onset of population activity tends to occur during the trough of oscillatory activity, and that deviations from this preferred relationship are related to changes in the timing of population activity and the speed of the resulting behavioral response. These results indicate that neuronal activity incurs variable delays as it propagates across neuronal populations, and that the duration of each delay is a function of the instantaneous phase of oscillatory activity. We conclude that the results presented in this paper are supportive of a general model for variability in the effective speed of information transmission in the human brain and for variability in the timing of human behavior.1 aCoon, W., G.1 aGunduz, A.1 aBrunner, Peter1 aRitaccio, A L1 aPesaran, B.1 aSchalk, Gerwin  uhttp://www.ncbi.nlm.nih.gov/pubmed/2697555101280nas a2200205   4500008004100000022001400041245008500055210006900140260000800209300001100217490000700228520068900235653001600924100001200940700001700952700001900969700001900988700001901007856004801026       2015                        eng d  a1741-255200aThe effects of spatial filtering and artifacts on electrocorticographic signals.0 aeffects of spatial filtering and artifacts on electrocorticograp  cOct  a0560080 v123 aElectrocorticographic (ECoG) signals contain noise that is common to all channels and noise that is specific to individual channels. Most published ECoG studies use common average reference (CAR) spatial filters to remove common noise, but CAR filters may introduce channel-specific noise into other channels. To address this concern, scientists often remove artifactual channels prior to data analysis. However, removing these channels depends on expert-based labeling and may also discard useful data. Thus, the effects of spatial filtering and artifacts on ECoG signals have been largely unknown. This study aims to quantify these effects and thereby address this gap in knowledge.10aYoung Adult1 aLiu, Y.1 aCoon, W., G.1 ade Pesters, A.1 aBrunner, Peter1 aSchalk, Gerwin  uhttp://www.ncbi.nlm.nih.gov/pubmed/26268446